Regarding the "Attention needed" this is to notify you that it is taking a long time to get a response back from the black list and this can effect the performance of SmarterMail.  Then can be due to the RBL having an issue or even the DNS server you are using.  If you see any performance issue with email deliver you may want to disable them for now.

 

As for the throttling can you please let me know how you have it configured?